(a) Field of the Invention
The present invention relates to a field emission display (FED) and a driving method thereof.
(b) Description of the Related Art
The flat panel display (FPD), which is an image pick-up device using cold cathode electrons as an electron emission source, has its quality greatly dependent upon characteristics such as the material of an electron emission region, or the structure.
FIG. 1 is a perspective view of a general FED. FIG. 2 is a cross-sectional view of the general FED shown in FIG. 1.
Referring to FIGS. 1 and 2, the general FED includes emitter 30 formed on rear substrate 1 as a source of electrons 60; cathode electrode 10 and gate electrode 20 for emitting electrons from emitter 30; and phosphorous surface 50 formed with red (R), green (G), and blue (B) phosphors and anode electrode 40 on the one side of front substrate 2 opposing rear substrate 1. The FED of this structure forms an electric field around the emitter using the voltage difference between the cathode and gate electrodes to emit electrons from the emitter and makes the emitted electrons collide with the phosphorous surface for light emission to realize a defined image.
Here, the cathode and gate electrodes are used as scan and data electrodes, respectively. Alternatively, the cathode and gate electrodes may be used as data and scan electrodes, respectively.
The FED is driven by the passive matrix method that involves light emission of pixels by a potential difference (between gate and cathode electrodes) caused by the driving pulses applied to a scan driver for driving horizontal scan electrodes and a data driver for driving vertical data electrodes. Furthermore, the gray scale is represented according to the overlapping width of the two driving pulses.
The FED applies a data signal only in one direction of the screen in applying data pulses to data lines, which include a resistance component to increase a voltage drop in the lower side of the screen. This voltage drop affects the brightness of the image because the FED uses the potential difference between gate and cathode electrodes for light emission. Accordingly, the left bottom of the screen having a high voltage drop relative to the right top appears dark, so that uniform brightness of the panel is not provided and the screen can appear rough and blotched.